[llvm] Refactor the LeaderTable structure in GVN into a properly encapsulated data structure. (PR #88347)

[Nikita Popov via llvm-commits]

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@@ -724,6 +724,68 @@ void GVNPass::ValueTable::verifyRemoved(const Value *V) const {
          "Inst still occurs in value numbering map!");
 }
 
+//===----------------------------------------------------------------------===//
+//                     LeaderMap External Functions
+//===----------------------------------------------------------------------===//
+
+/// Push a new Value to the LeaderTable onto the list for its value number.
+void GVNPass::LeaderMap::insert(uint32_t N, Value *V, const BasicBlock *BB) {
+  LeaderListNode &Curr = NumToLeaders[N];
+  if (!Curr.Entry.Val) {
+    Curr.Entry.Val = V;
+    Curr.Entry.BB = BB;
+    return;
+  }
+
+  LeaderListNode *Node = TableAllocator.Allocate<LeaderListNode>();
+  Node->Entry.Val = V;
+  Node->Entry.BB = BB;
+  Node->Next = Curr.Next;
+  Curr.Next = Node;
+}
+
+/// Scan the list of values corresponding to a given
+/// value number, and remove the given instruction if encountered.
+void GVNPass::LeaderMap::erase(uint32_t N, Instruction *I, BasicBlock *BB) {
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nikic wrote:

BB could be const here as well?

https://github.com/llvm/llvm-project/pull/88347